Telephone-exchange system



A. C. STUART.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED NOV. 11, I912. RENEWED MAY 3, 1921.

1,38%,980. v 'PatentedJuly 19,1921

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TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED NOV. 11, I912. RENEWED MAY 3,192

Patented July 19, 1921.,

10 SHEETS-SHEET 2.

allium A C. STUART.

TELEPHONE EXGHANGE SYSTEM. APPLICATION FILED NOV. 11, 1912. RENEWED MAY 3,1921.

1,384,980u Patented July 19, 1921 10 SHEETS*SHEET 3.

. -vII I FHH" A. C. STUART.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV-11,1912. RENEWED MAY 3,1921.

1,384,980. Patented July 19, 1921.'

10 SHEETS-SHEET 4.

A. CLSTUART.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED NOV. ll. 1-912. RENEWED MAY3, 1921,

1 3 4 9 0 Patented July 19, 1921.

I0 SHEETSSHEET 5.

A. C. STUART.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. 11. 1912. RENEWED MAY 3. 1921.

1 ,384, 980. Patented July 19, 1921.

I0 SHEETS-SHEET 6.

A. C. STUART.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED NOV. II, 1912. RENEWED MAY 3,1921.

1,384,980. Patented July 19, 1921.

10 SHEETS-SHEET 7.

I HIIHI- m A. C. STUART.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED NOV. 11. 1912. RENEWED MAY a,192'r.

Patented July 19, 1921..

10 SHEETSSHEET 8.

A. G. STUART.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED Nov. 11, 1912. RENEWED 11/1113, 1921.

1,384,980,, 11111111 July 19, 1921.

I0 SHEETS-SHEET 9.

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A. C. STUART.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. 11. 1912 RENEWED MAY 3,1921.

1,384,980.. P11611111 July 19, 1921.

l0 SHEETS-SHEET l0.

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ARTHUR C. STUART, OF CLEVELAND, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO JAMES R. GARFIELD, TRUSTEE, OF CLEVELAND, OHIO.

TELEPHONE-EXCHANGE SYSTEM.

Application filed November 11, 1912, Serial No. 730,752.

1 0 all whom it may concern Be it known that I, ARTHUR C. STUART, a citizen of the United States, and resident of Cleveland, Cuyahoga county, State of Ohio, have invented certain new and user'ul Improvements in Telephone-Exchange Systems, of which the following a specification.

My invention relates to telephone exchange systems, and especially to that class known as semi-automatic systems.

In systems of this class automatic switching mechanism controlled by operators is used in establishing connections between subscribers.

The object of my invention is to provide improved means in trunking from a manual switchboard to a semi-automatic exchange wherebysimultaneous calls from the manual exchange can be controlled without interference or loss of time.

Further objects of my invention provide improved means for releasing the selector and connector switches used at the semiautomatic exchange for establishing connections.

A. further object of this invention is to provide improved means in the connector circuit for flashing a signal at the operators position to notify the operator that the called line is busy.

in the present instance I have shown the method of trunking from a manual switchboard to a semi-automatic exchange. The operator at the magneto board receiving a call from a subscriber, planes the calling plug into a trunk jack which terminates at the semi-automatic exchange in a first selector switch. As soon as this connection is effected, the first selector switch and associated switches are controlled by the operator at the semi-automatic exchange who is provided with a suitable sending device.

After the connection is entirely established, the operator at the semi-automatic exchange jsautomatically disconnected from the main trunk and the switches are thereafter controlled by the operator at the magneto exchange or toll board. This op erator is provided with suitable means for supervising the connections.

My invention is illustrated in the accompanying drawings wherein,

Figure 1 shows a cord circuit and a pore Patented July 19, 1921.

Renewed May 3, 1921. Serial No. 466,530.

tion of a trunk circuit terminating in a jack at the manual switch board.

Fig. 2 shows the continuation of the trunk circuit at the semi-automatic exchange terminating in a first selector switch.

Fig. 3 shows a second selector circuit.

Fig. 1 shows a connector circuit with a party line selecting switch.

Fig. 5 shows a subscribers line and control circuit at the semi-automatic exchange.

Figs. 6 and 7 show the control circuits for the trunk and operators key-set switch.

F 8 shows the operators key-set and controlling circuit.

Fig. 9 shows the operators key-board and sending device.

10 shows the manner in which the various figures are to be arranged.

Referring now to Fig. 1, the answering plug P and the calling plug P are joined together by the conductors indicated in heavy lines for conversational purposes. These conductors are joined together through the contacts of keys 4117, 116, 425 and 130. hen the key 117 is operated, the operators telephone set is connected to the tip and sleeve conductors. When the key 416 is operated, generator is connected to the plug P hen the key 425 is operated, the generator is connected to the plug P lVhen the key .130 is operated, the repeating coil 120 and condenser 195 are inserted between the talking conductors of the plugs P and P When the plug P is inserted in the trunk jack J, the tip and sleeve conductors are connected to the trunk conductors e12, 413 and lamp 411 is connected to the wire $18, leading to a contact in relay 450 (Fig. 2). The insertion of the plug closes the contact springs 44% and completes the circuit of relay 135 (Fig. 2) so as to start a key-set switch in search of the trunk.

Referring now to Fig. 2, the trunk condwxtors 41:12, and 113 from the manual exchange are connected for conversational purposes to the wipers 44:? of the first selector switch through the windings of the repeating (oil 419 and condenser 121.

The wipers 4&8 act as test wipers and also form a part of the release circuit for the firstselector switch D. The relay 4A5 is actuated when the key-set switch picks out th trunk n 1 W 11 closes the circuit of relay 440. This latter relay disconnects relay 135 which is the starting relay and is originally energized when the plug P is placed in the jack J Relay 470 is the rotary repeating relay and responds to 1mpulscs from the sending device. 4551s the test relay and remains energized while the first selector switch D is picking out an idle second selector switch. Relay 450 is of a high resistance and is actuated when the called subscriber answers, and the action of this relay removes ground from the wire 118, extinguishing lamp 411 of the cord circuit, (Fig. 1).

Referring now to Fig. 3, the second selector switch E is operated first in a rotary direction to pick out the row, and then in a vertical direction to pick out an idle contact of the row and is similar to the first selector switch shown at D. Relay 81 is the repeating relay and responds to the impulses from the sending device. Relay 82 is the interrupter relay corresponding to relay 465 (Fig. 2). These respective relays are operated by their vertical magnets and when so operated open the circuit of the magnet itself, causing the switches to step vertically. Relay 83 is the test relay and remains energized until an idle connector switch is found. Relay 97- is for releasing and becomes energized as soon as the first selector switch places ground on the wire 96. This relay remains energized throughout the conversation and is disconnected when the calling party hangs up his rceiver and the op erator withdraws the plug P from the ack J When the relay 97 is released after the switch E has rotated, then the circuit of the release magnet 93 is closed and will restore the switch E to its normal position.

Referring now .to Fig. 4, the connector switch G is provided with wipers 390 which engage contacts leading to the talking conductors of the called line, and also with test wipers 391 leading to the cut-off relay of the called line. 305 and 310 are the repeating relays and respond to impulses from the sending device. 315 is a control relay and prevents battery being connectedto the wipers 390 while passing over busy contacts. 320 is the tip relay and responds when the called subscriber removes his receiver. 340 is the ringing relay operated by the commutator 370. 345 is the busy test relay and is operated when a busy line is found and when so operated, connects a suitable busy tone test to the calling subscribers line. The ac tion of this relay also operates the release magnet 365 restoring the connector switch G.

Action of relay 345 in addition removes relay 305 and connects ground to the tip conductor 300 through commutator 371. This intermittent ground, actuating relay 450, (Fig. 2) causes lamp 411 (Fig. l) to flash.

The controlling or party line switch is shown at F. The contacts and wipers of the portion J cut on the proper generators to either the tip or sleeve contact of the ringing relay 340 as the case may be. Thecontacts and wipers of the portion I serve to restore the distributing switch to its normal or idle position. The contacts and wipers of the portion H serve to connect ground to either the tip or sleeve contacts of the ringing relay 340. lVhen the portion J cuts on generator to the tip contact, the portion H cuts on ground to the sleeve contact, and when the portion J cuts on generator to the sleeve contact, the portion H cuts on ground to the tip contact. This arrangement makes it possible to ring subscribers bells which are connected from either the tip or sleeve side of the line to ground. When the switch F is in its normal position, the wiper of H rests on the contact 33 the wiper of I on the contact 336, while the wiper of J rests upon the contact 338. I

The contact 336 of this portion I is connected to the, interrupter 385 through the normally open cam springs controlled by the switch G; This arrangement will prevent the switch F from coming to rest so long as the switch G is in an off-normal position, as under these circumstances the wiper I would have no idle resting position. When the switch G is restored, the interrupter 385 is disconnected from the contact 336 and when the wiper reaches the contact under these circumstances, the switch F will be brought to rest. So long as the switch G is off-normal. then the switch F will continue to rotate and serve as a signal to the attendant that a connector switch is tied up.

Figs. 6 and 7 show the method of controlling the trunks leading from the manual exchange.

In Fig. 6 the switch C starts to rotate and pick out the trunk shown in Fig. 2 when the operator inserts the plug, in the jack. 254iv is the stepping magnet, which. when acting causes the switch Cto rotate. The relays 251 and 130 become energized when the wiper 255 of the switch C picks out the calling trunk. When these relays are energized, the stepping magnet is disconnected and the controlling circuits extended to the switch Y (Fig. 7 The switch Y picks out an idle key-set switch such as shown in Fig. 8. As soon as the switch 0 (Fig. 6) finds the trunk, the starting relay 130 (Fig. 7) closes the circuit, causing the stepping magnet 133 to operate. The action of relay 130 also connects the test relay 131 to the test wire 140 through the wiper 280 of the switch Y.

It will be noted that two segments 256 and 257 are provided in the switch G which the wiper 255 engages. One of these segments connects relays 251 and 130 in series while picking out a certain group of trunks, while the other segment connects second test re lay 252 in series withrelay 130 in picking out another group of trunks. In fact the switch C is provided with two test relays, namely, 251 and 252 each one becoming active when picking out a certain group of trunks, such as shown in Fig. 2.

In Fig. 7, the wiper 280 engages the two segments 281 and 282. While the wiper is in engagement with one segment, the test relay 131 for the key-set switches is used when picking out a certain group of key-set switches. This test relay 131 is connected to either one of the two segments 281 or 28-2, depending upon the action of relay 253 (Fig. 6). This relay 253 is energized by the action of relay 252 in picking out a certain group of trunks, and thereby con nects the test relay 131 to segment 282. When the test relay 251 is energized in serving a particular group of calling trunks, the relay 253 is not actuated and therefore the test relay 131 is connected to the segment 281. 7

Referring to Fig. 7, relay 132 becomes energized when the test relay 131 is actuated and connects ground to the winding of this test relay, thereby shunting it. Direct ground is thus placed on the wire 140 through the wiper 280 preventing any other Y switch picking out the same key-set switch. The action of relay 132 also connects ground to the lower portion of switch Y to wire 141 leading to the row contact of a key-set switch. These row contacts of the various key-set switches are not multi-- plied.

l/Vhen a key-set switch is picked out by a Y switch. ground is connected to the row contact of the selected switch but at no other.

This allows calls to come in from dill'erent groups of trunks at the same time without interference as only one row contact in. any key-set switch is grounded at the same time.

Other features in. connection with Figs. 6 and 7 will be made clear in the detail description of operation. The switch C (Fig. 6) serves to pick out the individual trunk in the group calling while the switch Y (Fig. 7) starts to pick out an idle key-set switch as soon as the first selection is completed.

The keyset switch starts to pick out the calling trunk. and after doing so, then both the switches C and Y are at once relieved. This method of selection brings the calls in from the different trunks without preferonce or the selection of the trunk to be first served depends upon the position of the arms of the switch G. I

Referring now to Figs. 8 and 9. the key set switch and operators key-board and sending device are shown. The key-set switch M carries the wipers 167, 168 and 169. The wiper 168 is the row wiper and when the switch, rotates, this wiper passes over a set of contacts until a busy one is found, whereupon the rotary action of the switch is discontinued and the switch starts to step in a vertical direction. While stepping vertically, the wipers 167 and 169 pass over vertical rows or sets of contacts. lit the lirst vertical step of the switch M, the row wiper 168 leaves the row contacts.

The wipers 167 serve to connect the tip and sleeve sides of the trunk shown in Fig. 2, over which the operator CODVEISGS with the calling subscriber, and over which the impulses are transmitted. Relay 158 connected to the row wiper 168 and is operated when the proper row contact is reached. The operation of this relay disconnects the retary magnet 165 and in its place connects the vertical magnet 16 1. Relay 15% is connected to the individual test wiper and is actuated when the proper individual test contact in the row or group is found and disconnects the vertical magnet causing the switch M to rest on contacts leading to the calling trunk. 156 is the signal relay and it pulls up in series with relay 445, (F ig. 2), when the trunk is picked out. The operation of the signal relay closes the circuits of the two lamps 243 and 244 (Fig. 9), notifying the operator of a call. 152 is the starting relay and is actuated when the switch Y picks out the idle switch MI 155 responds when the operator presses the button 248 and connects her telephone set across the tip and sleeve conductors of the trunk. 157 is operated when the button 247 is pressed and connects the starting wire controlled by the cam 231 to the stepping magnet 161, thereby causing the shifting switch arms to step over the banks N, O and P. This magnet is operated once at each rotation of the sending device and cuts on the impulses from the keyboard in proper sequence. The order of these impulses is as follows: At the first rotation of the sending device, impulses correspmiding to the thousands are sent over the tip side of the trunk. At the second rotation a single test impulse is sent over the sleeve side of the trunk. At the third rotation impulses corresponding to the hundreds are sent over the tip side of the trunk and at the fourth rotation a single test impulse is sent over the sleeve side of the trunk. ill the fifth rotation selective ringing impulses are sent over the tip side of the trunk, and at the sixth the tens impulses are sent over the sleeve side of the trunk. At the seventh rotation the units impulses are sent over the tip side of the trunk and at the eighth rotation a single test impulse is sent over the sleeve side of the trunk.

At the next rotation of the sending device the wiper of the portion P completes the circuit of relay 158 causing the shifting switch to rapidly rotate until it reaches its normal position. Just before reaching this closed while the operator is position the circuit of the release magnet 166 of the key-set switch M is energ zed thereby restoring. it to its normal position. Relay 163 is the interrupter relay operated by the magnets 164, 165 and 161.

The operators key-board shown in Fig. 9 consists of five rows of buttons, each row having ten buttons. Number 1 button of each row is connected to a contact operated by the cam 232. Number 2 button of each row is connected to a contact operated by the cam 233. Corresponding buttons in each row are connected to similar contacts. The contact controlled by the cam 232 is closed just long enough to keep the relay 160 (Fig. 8) energized, while one impulse is being transmitted by the commutator 242. If num ber 10 button is pressed, relay 160 would be closed by the cam 241 just long enough for ten impulses to be transmitted by the commutator 242. The contacts of the commutator 242 are connected directly to the normally open contact of relay 160, and when this relay is energized the impulses are connected to either the tip or sleeve sides of the trunk depending upon the position of the arm in regard to the N portion and of the switch.

The buttons or keys shown in these five rows, (Fig. 9) are of the usual locking and indicating type. When any one button of a certain row is depressed, it will release the button formerly depressed. The buttons 246, 247 and 248 are of the non-locking type and the contacts controlled by them are only pressing the but ton.

Other points in the various circuitswill be brought out in the detailed description of; operation which is as follows: Referring now to Fig. 1, when a subscriber at the manual switch-board desires to converse with some one in the semi-automatic exchange, the operator places the answering plug P into the calling ack associated with his line. I have not illustrated the calling subscrihers linecircuit as it can be of any desired type. It is only necessary that when the plug P is inserted in the jack of the calling line that the associated signal be disconnected. In this case the calling in signal is disconnected and the ring-oft" drop 460 which is connected to the tip and sleeve conductors of the cord, responds when the calling party wishes to become disconnected.

The operator places the calling plug P into an idle trunk jack J thereby closing 6 the contact springs 444. The closing of these springs completes the circuit of the lamp 414, or other multiple lamps, thus notifying the operators at the other positions that th1s particular trunk is busy. The closlng of the contacts 444 connects ground to relay 435 as follows: ground, 444, 434, cam springs 441, 432, contacts of relay 440, 433, 435 to battery B. The energizing of relay 435 complates the circuit of the stepping magnet 254, Fig. 6, as follows: battery B, contacts of relay 435, 79, contacts of relay 252, contacts of relay 251, 254, contacts of relay 250 to ground. The magnet 254 operating closes the circuit of relay 250, thereby opening its own circuit. The interruptions set up between the relay 250 and the magnet 254 causes the arms of the switch G to rotate. As soon as the calling trunk, (Fig. 2) is found, the test relay 251, (Fig. 6) and the starting relay 130, (Fig. 7) are closed as follows: battery B, contacts of relay 435, 62, wiper 255, segment 256, 251, 262, 679, 130 to ground. The operation of relay 251 disconnects the stepping magnet 254, thereby bringing the switch wipers of C to rest on contacts associated with the trunk, (Fig. 2). Battery is now connected to the individual test contact of the key-set switch, (Fig. 8) as follows: battery B, contacts of relay 435, 62, Wiper 258, 620 to the individual contact of the switch M, (Fig. 8).

The energizing of relay 130 connects battery B to the stepping magnet 133 through the contacts of relays 132 and 131. The circuit of the stepping magnet 133 is'interrupted by the action of the relay 134, thereby causing the switch Y to rotate and pick out an idle key-set switch such as shown in Fig. 8. As soon as a key-set is found, the circuit of relay 131 is closed as follows: ground, contacts or" relay 130, 137, 131, 259, contacts of relay 253, 260, segment 281, wiper 280, 140, 152, 195, cam springs 196 to battery B through the operators jack 400. The energizing of relay 131 disconnects the stepping magnet 133 and closes the circuit of relay 132. The action of relay 132 places ground to wire 146 loy-the path previously traced. This ground shunts ameni 131 and prevents other Y switches from 681m to rest on contacts leading to this wire 140 which is multipled to contacts of other Y switches. Relay 132 disconnects the stepplng magnet 133 after relay 131 falls back and prevents any further action of the switch Y. The action of rclay132 also connects ground to the row contact over wire 141.

The closing of the circuit of relay 152, (Fig. 8) connects ground to the rotary magnet 165 through the contacts of rela s 163 and 153, thereby causing the switch to rotate. As soon as the grounded row contact is engaged by the wiper 168, the circuit of relay 153 is closed. The action of relay 153 disconnects the rotary magnet and in its place connects the vertical magnet 164, thereby causing the switch M to step vertically until the individual test contact is found. The individual test contact is renrss aeso dered busy by the action of the switch C, (Fig. 6) placing battery on wire 620 leading to this individual test contact. As soon as this contact is found, the circuit of relay 154 is closed. This relay disconnects relay 152 and prevents any further action of the switch M. Relay 152 in turn disconnects relay 153, thereby placing relays 156 and relay 445, (Fig. 2) in series as follows; ground, contacts of relay 153, 175, contacts of relay 157, contacts of relay 155, 180, 156, 193, contacts of relay 15S, wiper 169, 59, 445 to battery B. The operation of relay 445 closes the circuit of relay 440 and this latter relay acting disconnects relay 435. Relay 435 being disconnected in this manner, opens the circuits of relays 251 and relay 130 respectively in Figs. 6 and 7. As soon as relay 251 falls back, the circuit of the stepping magnet 254 is again in condition to be actuated by calls from other trunks. Relay 130, (Fig. '7) fallin back unlocks relay 132, which in turn places the stepping magnet 133 in condition to be operated by other calls.

It will be noted from the foregoing description of operation that the switch Y is the main switch for picking out idle key-set switches, while switch C is an intermediate switch enabling quick cooperation between the trunks and key-sets. As soon as the key-set switch picks out the trunks, the main switch Y and the intermediate switch C are at once relieved and are ready to control other calls.

The wire 79 shown in Fig. 6 is common to a group of primary trunks. There may be ten of these trunks in this particular group. A. call from any trunk in this group will bring the test relay 251 into action. A wire 779 leads to another group of trunks. There may be ten trunks in this group and a call from any one of these trunks will place the test relay 252 in condition to be operated at the proper time. The relay 253 is used in conjunction with the test relay 252 and serves to. shift the test relay 131 (Fig. i) to a particular group oi? key-set switches. The wiper 280 and segment 281 with which it cooperates serves to pick out a. certain group 01'' key-set switches. There may be ten of these switches to a group and a similar group connected by means of the segment 282. 1

Relay 156 becoming energized closes the circuits of the two lamps 243 and 244, (Fig. 9) notifying the operator of a call. The operator upon receiving this signal, presses the button 248 operating relay 155, thereby connecting her telephone set across the tip and sleeve conductors of the trunk. The action of relay 155 disconnects the signal relay 156, thereby extinguishes lamps 243 and 244, but at the same time lighting the lamp 245. Belay 156 becoming disconnected allows relay 445 (Fig. 2) to fall back and close the tip and sleeve conductors of the trunk so'as to allow the operator to converse with the calling subscriber.

Each operator is provided preferably with three key-sets such as shown in Fig. 9, enabling her to handle calls without loss of time. While a call. is going through on one key-set she can receive calls on the other two.

The cams of the sending device shown at 230 to 241 inclusive may be common to a group of key-sets. The commutator 242 is preferably individual to one key-set or to one operator.

In Fig. 8, the plug connected to the receiver of the operators telephone set is shown as withdrawn from the jack 400, however it is to be understood that when the operator is on duty the plug is inserted and the jack springs are closed.

In the present instance I have shown the exchange to be of 10,000 lines capacity and in ase oi larger exchanges it would be necessary to add additional rows of buttons to the operators key-board and insert additional selector switches.

The operator after getting the proper number from the subscriber presses one button in each row so as to set up the number corresponding to that desired and then presses the starting button 247. ing of this button closes the circuit of relay 157 as follows: ground,247, 186, 157, 193 contacts of relay 158, 170, 169, 59, 445 to bat tery B. The relay 445 again operating opens the trunk conductors to prevent the calling subscriber hearing the impulses.

The operating of relay 157 disconnects relay 155, extinguishes lamp 245 and causes the lamp 244 to light. The action of this relay also connects the starting wire 189 to the contact operated by the cam 231 to the stepping magnet 161. As soon as the cam contact springs are closed, the wipers of the shifting switch at V, 0, P take one step and connect the impulse wire 191 to the tip side of the trunk 150 through the contacts of relay 160.

' If number 9 button in the row R is pressed, the relay 160 will be held energized by the operation of the cam 240 until nine impulses have been transmitted by the commutator 242. These impulses operate the rotary relay 470, (Fig. 2) as follows: ground, 242, 191, 190, 192, contacts of relay 160, N, 150, 167, 60, 422, cam springs 442, 470 to battery B. The relay 470 responding to these impulses closes the circuit of the rotary magnet 475, causing the first selector switch D to rotate and bring the wipers opposite a group of trunks in the ninth row.

After these rotary impulses have been sent, the starting cam 231 causes the shifting switch to take another step, thereby connecting wire 198 to the sleeve side of the trunk The press- 151. The relay 160 is held energized by the action of the cam 230 until a single impulse is transmitted. This impulse closes the circuit of relay 455, (Fig. 2) as follows: ground, 242, 191, 190, 192, contacts of relay 160, 198, N, 151, 167, 61, cam springs 442, 438, .455 to battery B. The operating of relay 455 closes the circuit of the vertical magnet 480 as follows: Battery B, contacts of relay 465, contacts of relay 455, 480 to ground. The mag,

net 480 acting closes the circuit of relay 465, which in turn opens the circuit of the magnet itself. The action set up between the relay and the magnet causes the latter to vibrate and to step the switch D vertically. When the circuit of relay 465 is closed by the action of themagnet 480, the circuit of re lay 455 is itself partially opened, but it will remain energized so long as the test wiper 448 is passing over grounded or busy contacts. While the relay 465 is operated and the wiper 448 comes to an idle contact, the relay 455 will at once become deenergized and disconnect the vertical magnet 480. The controlling of the test relay 455 in this manner insures a full step of the magnet 480 as the wiper 448 fully engages the test contacts before the circuit of the relay 455 is opened.

. nector swltch (r to rotate and come opposite by the action of the relay 465.

As soon as the switch D takes its first vertical step, or while in the 'act of taking this step, the cam springs 442 are opened, there by disconnecting relays 455 and 470 respectively fromthe tip and sleeve sides of the trunk.

I At thethird rotation of the sending device impulses corresponding to the hundreds are sent over the tip side of the trunk to the second selector, (Fig. 3) thereby operating relay 81. This relay is connected to the tip side of the trunk 90 through the cam springs 88. The action of relay 81 closes the circuit of the rotary magnet 85 causing the switch E to rotate and bring its wipers opposite a row of contacts leading to connector switches.

At the fourth rotation of the sending device a single test impulse is sent over the sleeve side of the trunk operating relay 83. The action of this relay closes the circuit of the vertical magnet 84, causing the switch E to step vertically until an idle connector switch is found. The test relay 83 is con trolled in the same manner as the test relay 455, (Fig. 2). At the first vertical step of the switch E the cam springs 88 are opened thereby disconnecting relays 81 and 83 recloses the circuit of the stepping magnet 360 of the party line distributing switch F as follows: ground, 321, contacts of relay 330, 323, 360, 318, contacts of relay 320 to battery B. The switch F takes a number of steps corresponding to the impulses transmitted from the sending device.

In the present instance I have shown the generator 356 connected to the first two contacts in the bank J so that if either one or two impulses are transmitted, this same generator will remain connected to the tip side of the trunk 304. If six or seven impulses are transmitted, this same generator will be connected to the tip side of the trunk 302.

The action of relay 310 also closes the circuit of relay 315 as follows: battery B, 319, 315, contacts of relay 305, 306, 102, (Fig. 3), 89, contacts of relay 82 to ground.

At the sixth rotation of the sending device impulses corresponding to the button pressed in the row T are sent over the sleeve side of the trunk operating relay 305. The operation of this relay unlocks relay 315 and closes the circuit of the rotary magnet 355 as follows: battery B, contacts of relay 305, 314, cam springs 380, 316, 355 to ground. The rotary ma net operating causes the cona group of contacts in which the desired line is connected. The action of relay 305 also closes the circuit of relay 330, which disconnects the stepping magnet 360 of the switch F and in its place connects the vertical magnet 350. 7

At the seventh rotation of the sending device vertical impulses are sent over the tip side of the trunk operating relay 310 the second time. This relay closes the circuit of the vertical magnet 350 causing the switch G to step vertically and bring the wipers into engagement with contacts leading to the desired line. The action of relay 310 again energizes relay 315, preventing annoying clicks to parties talking while the wipers are passing over contacts of busy lines. When the switch G takes a vertical step, the cam spring 380 operates and disconnects the rotary magnet At the eighth rotation of the sending de vice a single test impulse is sent over'tl'ie sleeve side of the trunk operating relay 305 a second time. This relay operating con" nects the test relay 345 directly to the test wiper 391. If the called line is busy, this relay 345 will become energized, lock itself to ground to the test wire 306. The action of this relay places ground on the release magnet 365 and causes the switch G to restore and also connects a suitable busy tone test to the calling subscriber, notifying him that the line is busy. The action of this test relay 345 alsoconnects ground through a suitable commutator. or interrupting device. The ground being placed on the trunk isseceso flash, thus notifying the operator that the called line is busy. 1

In case the called line is not busy, the relay 3 1-5 will not be affected. Relay 305 acting' the second time unlocks relay 315 and in I falling back places the relay 325 in series withthe cutoff relay 1, (Fig. 5) by the following path: battery 1 313 con" rs relay 315, 312, 325, 311 back contact of relay 305, 308, 391, 107, 1 to ground. The action of relay 108 disconnects the line relay of the calledline. The action of relay 325 closes the sleeve side of the trunk and disconnects the repeating relay 310. The action of this relay also places battery to the winding of the tip relay 320 and closes the circuit of the ringing relay 340 as follows: ground, commutator 370, 340, 326, contacts of relay 325, 32 1-, contacts of relays 330 and 315, 322, vertical magnet 350 to battery B. The action of this ringing relay connects the generator to the called line, thus ringing the subscribers bell A-A at intervals. s

At the next rotation of the sending device the relay 158, (Fig. 8) is connected to bat tery through the bank P. The action of this relay places ground to the magnet 161and also unlocks relay 157i The magnet 101 vibrates rapidly and causes the: shifting switch to rotate until the wipers reach their normal resting position. ing this position, however, the wiper of the portion P places the relay 158 in series with the release magnet 166. The action ofjthis magnet causes the switch M to restore and disconnect the operatoflskey-set from the trunk. V

When the called subscriber removeshis receiver during the silent interval he energizesirelay 320. The action of this relay unlocks rela 330 and d sconnects relay 305 and closes tie tip side of the trunk. The falling back of relay 330 disconnects the ringing rolay3 i0, The calling and calledsubscriber are now able to converse without interference over the talking circuit ]I1Cll- ,cated throughout the various figures by the heavy lines.

"When the called subscriber hangs up his receiver the relay 320 falls back and the circuit of the magnet 360 is closed as follows: ground, commutator 353, 1,398, contacts of relay 330, contacts of relay 3123, 321, the contacts of relay 330, 323, 360, 318 to battery 13, through the contacts of relay 320. The magnet 360 will continue to vibrate un til the wiper of the portion T rests on the contact 336 providing the switch G is re stored, removing; interrupted current from.

this resting contact. Just before the wiper at I reaches the resting contact, the wiper Just before reachatH closes the circuit of the release magnet- 365 as follows: battery B, 365, 332, H, 32;- tog-round, through the contacts of relay 315. The action of magnet 365 restores the switch a G to its normal position.

The. calling subscriber ringing-off throws the ring-off drop 160, (Fig. 1) notifyingtlm operator that he is through talking.

l henfthe culled subscriber hung up his receiver, the relay 50 fell back, thus closing the circuit of the lamp 4:11, 1) notifying the operator of the fact. When the called subscriber answers his telephone, and while his receiveris off the hook, therelay 4.50 remainsenergized. in multiple with the tip relay: 320. This relay remaining; energized throughout the conversation, keeps the lamp 411, (F 1g. 1) extinguished. I

e operator getting these disconnect sign nals, withdraws the plug P from the jack J therebyremoving ground from relay This relay in falling back closes the circuit of the release magnet as follows: Battery 13, contacts of relay 445', 127, contacts of relay 4-10, 185, 436, wipers which are short circuited by. the bank contacts al29, to ground, through contacts of relay 435. The circuit of magnet 435 willremainclosed un. til the. wipers 148 leave the contacts. As

soon as these wipers leave the contacts, the

the operator also releases the connector switch. This release is brought about as follows: l/Vhen the second selector switch, (Fig. 3) restores, ground is removed from the test wire thereby unlocking the control relay 330 .just asthough the called subscriber had answered andv energized the tip relay 320. The relay 330 falling back in this manner closes the circuit of the step pingmagnet 360 the same path as for" .merly traced, thereby restoring allfparts of the connector switch to its normal position. i 1

Having described my' invention what I claim and desire to secure by Letters-Patentis, a i

in a telephone, exchange system, the

The cirs combination of an operators position,

signal at. said position, wanted subscribers lines, means for establishing a connection from said position to a wanted line com prising); a selector and a, connector switch,

a single test relay associated with ,said con nector switcl1,.means for operating said relay 111 case the wanted line 1s busy,,1ntermiting and a called 'subscribers line, an op-' tent means associated with said connector switch, 'Silhl intermittent means being connected immediately through the contacts of said relay to cause the intermittent operation of said'signal. v j

2. In a telephone (-mchange system, a callerators position, a signal at said position, automatic switching mechanism including selector and connector switches for extend'' mg theconnectlon from the calhng to the alled line, test relay associated with "said connector switch, means for connectingsaid test relay directly to the line terminals of the wanted line, means for operating said relay in case the called line is busy, and

means connected directly through the contacts of said relay to cause the intermittent operation oi said signal. v

3. In a telephone exchange system, the combination or a manual exchange switchboard provided with jaclreicalling subscribers lines terminating in certain of the jacks, an operators cord circuit having 'anianswering plug and a calling plug connected thereto,-a visual signal associated with said'cord jcircuit, automatic switching mechan1smineluding first selectorQsecond selector and connector I switches, links interconnecting said switches, trunk lines terminating in other :jacks on the manual switchboard and in the first selector witch, wanted: subscribers lines terminating in the vconnector 'SWllJCll, and means assoclated with the connector swltch and arrangedto operate said signalin the cord circuit to notify the operator at the manual exchange that the called or wanted line is busy.

4;.ln a telephone exchange system, the

combinationof amanual exchange switchboard prov ded wlth ]acks, calling SllbCIllF ers lines terminatin in certain of the 'acks anoperators cord circuit having an answering plug and a'calling plug, a visual signal associated with the calling plug of the cord circuit, automatic swltchmg mechanism-comprising first selector, second selector, and

connector switches, interconnecting link cir-' cuits, trunk lines-terminating in certain jacks on themanual exchange swltchboard and in the first selector switch, wanted subscribers lines termmatmgin the connector switches, and means for intermittently op erating the signal in the cord circuit, said meansbeing actuated when the connector switch connects the link circuit of thecallinga subscriber with a busy called or wanted subscribers line. 7 1

In a telephone exchange system, the

combination of a manual exchange switch-i board provided with jacks, calling subscribers lines termmatlng in certain of the jacks,

an operators cord circuit havingan answer ing plug and a calling plug, an operators telephoneiset arranged to be connected with the conductors of the cord circuit, a's ignal also connected with the conductors' of the cord circuit and responding when the calling subscriber wishes to become disconnected, a supervisory lamp connected to the calling plug of the operators cord circuit, automatic switching mechanism comprising first selector, second selector and connector switches, link circuits interconnecting said switches, trunk lines terminating in certain jacks on said manual switchboard and in the first selector switch, wanted subscribers lines terminating in said connector switches, meanswhereby said lamp is energlzed when the calling plug of a cord circuit is insertedin a jack connected to a'trunlr line, and means associated with the connector switch for intermittently fiashingsaid lamp so as to notify the manual operator that the called or wanted line is busy.

61111 a telephone exchange system, the combination of a manual exchange switchboard provided with jacks, calling subscribers lines terminatingin certainotthe jacks-f an operators cord circuit having an answering plug and a calling plug, a supervlsory' signal connected with the cord clrcuit, automatic switching mechanism including first selector, second 1 selector and connector switches, linkcircuits interconnecting the switches, trunk lines terminating incertain other jacks on the manual switchboard and in the switching mechanism, wanted subscribers ilines' terminating in the connector switches, means whereby said supervisory signal is energized when the calling plug is inserted in a geek connected to a trunk l1neterminating in the switchmg mechanism,

means for deenergizing the signal when a wanted subscriber responds, and means for intermittently disabling the signal and for" connecting a busy tonetest to the calling subscrlbers line to simultaneously notlfy the manual operator and the calling subscriber that the wanted or called line is busy.

7. In a telephone eiichangesystem, the a combination of a manual exchange switchboard provided with jacks, calling sub-- scribers lines terminating ini certain of the jacks, .a manual operators cord crrcurthaving an answering plug and a. calling plug, 1

means for notifying the manual operator when the calling subscriber desires to be dlsconnected, a supervlsory lamp mthe operatorscord circuit, automatic switching incense lamp is energized when the calling plug is inserted into a ack connected to a trunk lineterminating ina first selector switch,

electrically operated means actuated when the wanted subscriberresponds tor deenergizing the supervisory lamp, and means for intermittently flashing the supervisory lamp, connecting a busy signal to the calling subscribers circuit and restoring the conncctor switch comprising a relayoperated when the contactorsof the connector switch engage the contacts of a busy called line, a grounded commutator connected in circuit with said electrically operated means by said relay, anda release magnet energized by the operation of said relay.

8. In a telephone exchange system, a call: ing subscribers line, trunk lines, means for connecting the calling subscribers line to an idle one of said trunk lines, operators key sets, automatic key set switches associated withsaid key sets, an auxiliary automatic switch for picking out an idle key setswitch, anintermediate automatic switch associated with said auxiliary switch for designating the trunk-to be selected by the idle key set switch. i

9. In a telephone exchangesystem, a calling subscribefls line, a wanted or called subscribefis' line, automatic switching mechanism in which the wanted or called subscribcrs line terminates, trunk lines adapted to be connectedwith the calling subscribefis line, operators key sets, automatic key set switches associated with said key sets, an

au\iliary automaticswitch for picking out an idle key set switch, an intermediate automatic switch associated with said auxiliary switchqfor designating the-trunk to be se- 'lGCtGddW the idle key set switch.

10. In a telephone exchange system, the combination of a manual exchange switch hoardi'provided with jacks, calling subscrihers lines tern'iinating in certain oi the jacks, semi-automatic operators key sets, automatic key set switches associated with said key sets, an auxiliary autoi'i'iatic switch for picking out an idle key set switch, an intermediate automatic switch associated with the auxiliary switch and groujfis of: trunk lines terminating in certain other jacks on the manual. switchboard and at con-- tacts on said intermediate switch, the intermediate switch being arranged to pick out calling trunk lines.

ii. In a telephone exchange system, the combination oi a manual exchange switchboard provided with jacks, calling subscribers lines tern'iinating in certain Oi the jacks, an operators cord circuit having an answering plug and. a calling plug, a semiautomatic operatoris key set, automatic key set switches associated with said key i auxiliary automatic switch adapted ctuatcd to pick out an idlekey set switch,

an intermediate automatic switch associated with the auxiliary switch, groups of trunk lines terminating in jacks atgthe manual switchboard, a conductor associated with said group of trunks and connected to the starting mechanism for said intermediate switch to operate the latter when the calling plug of the cord circuit is inserted into a jack associated with any one of said trunks, and means whereby the intermediate switch is adapted to serve a plurality of groups of trunks. v r p 1 2. In a telephone exchange system, the combination of a manual 'switchboardprovided with jacks, calling subscribers lines terminating in certain of the jacks, a manual operators cord circuit having an answering plug and a calling plug, a semi-automatic operators keyboard provided with key sets, automatic key set switches associated with said key sets, auxiliary automatic switches adapted to select an idle key setswitch, groups of primary trunk lines terminating in certain jacks on the manual switchboard, an intermediate automatic switch in which the groups of trunk lines terminate and which is adapted to select the calling trunk, means for actuating said switch when said calling plug is inserted in a ack associated with a trunk of one of said groups, a pluralit-y oi": elementsonthe intermediate switch associated with, separate groups of trunks, and adapted to determinethe auxiliary switch to be utilized, and vmeans for displacing the elements not connected in circuit so that other connections to the intermediate switch may not bemade. i

13. In a telephone exchange system,,the combination of a manual switch board provided with jacks, subscribers calling lines terminating in certain other jacks, a manual operators cord circuit provided with 1111 swering and calling plugs, a semi-automatic operators keyboard having key sets, automatic key set switches associated with the key set-s, auxiliary automatic switches adapted when actuated to select an idle key set switch and comprising two banks of contacts, one of said banks being associated with the multiple contacts of saidkey set switches, the other bank being connected with the row contact of the key set switches, wipers operating over the contacts ofsaid auxiliary switch, groups of trunk lines terminating in other jacks in the manual switchboard, an intermediate switch which said groups of trunk lines terminate and adapted to selecta calling trunk, means whereby the auxiliaiy switchoperating is disabled when a trunk of a. certain group is selected by the intermediateswitch until the auxiliary switch finds an idle selector switch, means for releasing the auxiliary switch until an idle selected switch istound and permitting the intermediate switch to pro- 

